1. Field of the Disclosure
This disclosure relates generally to plenoptic imaging systems and, more particularly, to the calibration of plenoptic imaging systems.
2. Description of the Related Art
The plenoptic imaging system has recently received increased attention. It can be used to recalculate a different focus point or point of view of an object, based on digital processing of the captured plenoptic image. The plenoptic imaging system also finds application in multi-modal imaging, using a multi-modal filter array in the pupil plane of the primary imaging module. Each filter is imaged at the sensor, effectively producing a multiplexed image of the object for each imaging modality of the filter array. Other applications for plenoptic imaging systems include varying depth of field imaging and high dynamic range imaging.
However, the architecture of a plenoptic imaging system is different from that of a conventional imaging system, and therefore requires different calibration and processing procedures. Several challenges are found in the processing of plenoptic images. First, the alignment of the microlens array is never perfect and the effect of rotation of the microlens array relative to the sensor array is quite observable. This rotation introduces a large amount of difficulties for image reconstruction because the data points do not fall onto a regular sampling grid. Additionally, for different applications, different focus settings may be used. For plenoptic imaging systems, a change in focus affects the angle of the incident light which can impact the effective pitch of the image towards its periphery, by a small but cognizable amount.
Thus, there is a need for calibration techniques for plenoptic imaging systems.